1. Field of the Invention
The present invention relates to sealing arrangements for telescopically inter-fitted parts and, in particular, to sealing arrangements for use in valves.
2. Description of the Prior Art
Valves, such as angle valves, are frequently provided with removable or detachable port fittings. In such cases, the seal joint between the valve body and the removable port fitting frequently develops leaks because of the strain or force applied to the fitting when it is coupled to exterior piping. In many applications, such as for tank cars or trucks or barges, the couplings are effected by operators, sometimes poorly trained, using large wrenches and hammers which exert substantial forces and moments which can create a leakage path between the valve body and the detachable port fitting. Also, a slight misalignment of the parts can result in a leak.
Typically, the joint between the valve body and the removable port fitting is sealed with a flat gasket and/or an O-ring, but this type of seal has proven to be insufficient to ensure a leak-free joint. It is known to provide more than one seal ring in a seal joint, but this also has proven to be insufficient to ensure leak free joints in the removable port fittings of large angle valves.